Parliamentary by-elections in the United Kingdom occur when a Member of Parliament (MP) vacates a House of Commons seat (due to resignation, death, disqualification or expulsion) during the course of a parliament.
Although the history of Parliament is much older, most of these records concern only the period since 1945. Earlier exceptional results are listed separately.
Parliaments of England, Scotland, Ireland and the various unions of these Kingdoms had been assembled since the medieval period, though these bodies only gradually evolved to be democratically elected by the populace and records are incomplete. England and Wales had numerous "rotten boroughs" with tiny and tightly controlled electorates until the Reform Act of 1832. The most recent significant expansions of the electoral franchise were the Representation of the People Act 1918 which allowed some women to vote for the first time and greatly expanded the franchise of men, overall more than doubling the size of the electorate, and the Representation of the People (Equal Franchise) Act 1928 which expanded the franchise of women to be equal to that of men.
Furthermore, there are various additional factors complicating comparisons between earlier results and modern cases. Among the most significant aspects of historical elections which are no longer present are:
Since 1945, the legal and general political situation regarding by-elections has been broadly stable, allowing for meaningful comparison of records.
These records include those from Northern Ireland. However, the politics of Northern Ireland is mostly separate from that of Great Britain so comparisons can be problematic.
For comparison purposes the following definitions have been adopted.
For more information about what is meant by the term "swing", see Swing (United Kingdom)
|1983 Bermondsey by-election||44.2||Labour||Liberal|
|2014 Clacton by-election||44.11||Conservative||UKIP|
|1973 Lincoln by-election||43.01||Labour||Democratic Labour|
|1967 Hamilton by-election||37.9||Labour||SNP|
|2012 Bradford West by-election||36.6||Labour||Respect|
|1993 Christchurch by-election||35.4||Conservative||Liberal Democrats|
|2021 North Shropshire by-election||34.2||Conservative||Liberal Democrats|
|1988 Glasgow Govan by-election||33.1||Labour||SNP|
|1972 Sutton and Cheam by-election||32.6||Conservative||Liberal|
|1979 Liverpool Edge Hill by-election||30.2||Labour||Liberal|
|2022 Tiverton and Honiton by-election||29.9||Conservative||Liberal Democrats|
|1994 Dudley West by-election||29.2||Conservative||Labour|
|2003 Brent East by-election||28.9||Labour||Liberal Democrats|
|1993 Newbury by-election||28.4||Conservative||Liberal Democrats|
|2014 Rochester and Strood by-election||28.31||Conservative||UKIP|
|2004 Birmingham Hodge Hill by-election||26.73||Labour||Liberal Democrats|
|1962 Orpington by-election||26.3||Conservative||Liberal|
|1973 Ripon by-election||25.3||Conservative||Liberal|
|2021 Chesham and Amersham by-election||25.1||Conservative||Liberal Democrats|
|1991 Ribble Valley by-election||24.7||Conservative||Liberal Democrats|
|1981 Croydon North West by-election||24.2||Conservative||Liberal|
|1994 Dagenham by-election||23.1||Conservative||Labour|
|1999 Hamilton South by-election||22.63||Labour||SNP|
|1976 Walsall North by-election||22.5||Labour||Conservative|
|2008 Glasgow East by-election||22.5||Labour||SNP|
|1996 South East Staffordshire by-election||22.1||Conservative||Labour|
|1994 Barking by-election||22.0||Conservative||Labour|
|2016 Richmond Park by-election||21.72||Conservative||Liberal Democrats|
|2004 Leicester South by-election||21.5||Labour||Liberal Democrats|
|1990 Mid Staffordshire by-election||21.3||Conservative||Labour|
|1968 Dudley by-election||21.2||Labour||Conservative|
|1977 Ashfield by-election||20.9||Labour||Conservative|
|1999 Leeds Central by-election||20.53||Labour||Liberal Democrats|
|1990 Eastbourne by-election||20.0||Conservative||Liberal Democrats|
1 By-elections where the seat was held by the incumbent MP.
2 By-elections contested by the incumbent MP, who failed to gain re-election.
3 By-elections where the seat was held by the incumbent party.
A party's share of the vote at a general election is not always matched at subsequent by-elections, but given the five-year maximum term of a Parliament, reductions of 20% or more are unusual. Those of 25% or more are listed below:
|1948 Glasgow Camlachie by-election||51.3||Ind. Labour Party||Unionist gain|
|1983 Bermondsey by-election||37.5||Labour||Liberal gain|
|1969 Birmingham Ladywood by-election||33.4||Labour||Liberal gain|
|1993 Christchurch by-election||32.5||Conservative||Liberal Democrats gain|
|1946 Glasgow Bridgeton by-election||32.1||Ind. Labour Party||Ind. Labour Party hold|
|1958 Rochdale by-election||31.7||Conservative||Labour gain|
|2021 North Shropshire by-election||31.1||Conservative||Liberal Democrats gain|
|1994 Dudley West by-election||30.2||Conservative||Labour gain|
|1995 North Down by-election||29.9||NI Conservatives||UK Unionist gain from Popular Unionist|
|1967 Hamilton by-election||29.7||Labour||SNP gain|
|2004 Birmingham Hodge Hill by-election||29.6||Labour||Labour hold|
|1961 Paisley by-election||29.5||Unionist||Labour hold|
|2003 Brent East by-election||29.4||Labour||Liberal Democrats gain|
|1993 Newbury by-election||29.0||Conservative||Liberal Democrats gain|
|1968 Caerphilly by-election||28.7||Labour||Labour hold|
|1999 Hamilton South by-election||28.7||Labour||Labour hold|
|2014 Clacton by-election||28.4||Conservative||UKIP gain|
|1962 West Lothian by-election||28.3||Unionist||Labour hold|
|1979 Liverpool Edge Hill by-election||28.1||Labour||Liberal gain|
|1958 Torrington by-election||27.7||Conservative||Liberal gain|
|1968 Oldham West by-election||27.6||Labour||Conservative gain|
|2009 Norwich North by-election||26.7||Labour||Conservative gain|
|1933 Fulham East by-election||26.6||Conservative||Labour gain|
|1972 Sutton and Cheam by-election||26.2||Conservative||Liberal gain|
|1948 Glasgow Gorbals by-election||25.5||Labour||Labour hold|
|2019 Peterborough by-election||25.5||Conservative||Labour hold|
|1962 West Derbyshire by-election||25.2||Conservative||Conservative hold|
|2004 Leicester South by-election||25.2||Labour||Liberal Democrats gain|
In the 1934 Merthyr by-election the Independent Labour Party share dropped from 69.4% in the 1931 general election to 9.8% (a record 59.6% loss) losing the seat to the Labour Party. However, the 1931 election had no Labour Party candidate, and the MP, R. C. Wallhead, had previously been elected as a Labour candidate in prior elections, when the ILP was affiliated to Labour. Prior to his death, Wallhead joined the Labour Party, so this result could be classed as a Labour hold.
The 1919 East Antrim by-election saw the Irish Unionist party face its first Unionist opposition in the seat since 1906 (in the 1918 general election the heavily unionist area gave the Irish Unionist 94.6% of the vote in a contest with a Sinn Féin candidate). An Independent Unionist candidate won the seat, with the Irish Unionist share dropping by 52.8%
Worst results for other parties:
|2021 Hartlepool by-electiona||24.6||Reform UK||Conservative gain from Labour|
|1982 Belfast South by-election||22.4||UUP||UUP hold|
|2014 Heywood and Middleton by-election||17.6||Liberal Democrats||Labour hold|
|2009 Glasgow North East by-election||14.0||Socialist Labour||Labour gain from Speaker|
|2017 Copeland by-election||9.0||UKIP||Conservative gain from Labour|
|1963 Kinross and Western Perthshire by-election||7.7||SNP||Unionist hold|
|1986 Newry and Armagh by-election||7.7||Sinn Féin||SDLP gain from Ulster Unionist|
|1963 Swansea East by-election||5.3||Plaid Cymru||Labour hold|
|Election||Increase in Share||Party||Result|
|1986 East Londonderry by-election||56.0||UUP||UUP hold|
|2012 Bradford West by-election||52.8||Respect||Respect gain|
|1983 Bermondsey by-election||50.9||Liberal||Liberal gain|
|1986 South Antrim by-election||48.4||UUP||UUP hold|
|1986 East Antrim by-election||47.5||UUP||UUP hold|
|1986 North Antrim by-election||43.2||DUP||DUP hold|
|2016 Batley and Spen by-election||42.6||Labour||Labour hold|
|1972 Sutton and Cheam by-election||39.0||Liberal||Liberal gain|
|1993 Christchurch by-election||38.6||Liberal Democrats||Liberal Democrats gain|
|1988 Glasgow Govan by-election||38.4||SNP||SNP gain|
|2022 Tiverton and Honiton by-election||38.1||Liberal Democrats||Liberal Democrats gain|
|2021 North Shropshire by-election||37.1||Liberal Democrats||Liberal Democrats gain|
|1979 Liverpool Edge Hill by-election||36.8||Liberal||Liberal gain|
|2014 Heywood and Middleton by-election||36.1||UKIP||Labour hold|
|1986 Belfast East by-election||35.7||DUP||DUP hold|
|1986 Belfast North by-election||35.3||UUP||UUP hold|
|1973 Glasgow Govan by-election||31.6||SNP||SNP gain|
|1986 Lagan Valley by-election||31.5||UUP||UUP hold|
|2021 Chesham and Amersham by-election||30.4||Liberal Democrats||Liberal Democrats gain|
|1973 Ripon by-election||30.4||Liberal||Liberal gain|
|2016 Richmond Park by-election||30.3||Liberal Democrats||Liberal Democrats gain|
|1981 Croydon North West by-election||29.5||Liberal||Liberal gain|
|1968 Caerphilly by-election||29.3||Plaid Cymru||Labour hold|
|2003 Brent East by-election||28.5||Liberal Democrats||Liberal Democrats gain|
|1994 Dudley West by-election||28.0||Labour||Labour gain|
|1987 Greenwich by-election||27.9||SDP||SDP gain|
|1972 Merthyr Tydfil by-election||27.4||Plaid Cymru||Labour gain|
|1966 Carmarthen by-election||27.4||Plaid Cymru||Plaid Cymru gain|
|1991 Ribble Valley by-election||27.1||Liberal Democrats||Liberal Democrats gain|
|1994 Monklands East by-election||26.9||SNP||Labour hold|
|2022 Southend West by-election||26.9||Conservative||Conservative hold|
|2004 Birmingham Hodge Hill by-election||26.1||Liberal Democrats||Labour hold|
|2008 Glasgow East by-election||26.1||SNP||SNP gain|
Winning shares of the vote above 90%, since 1918:
|Ernest Gates||Conservative||1940 Middleton and Prestwich by-election||32,036||98.7|
|Ian Paisley||DUP||1986 North Antrim by-election||33,937||97.4|
|John Craik-Henderson||Conservative||1940 Leeds North East by-election||23,882||97.1|
|Charles Key||Labour||1940 Bow and Bromley by-election||11,594||95.8|
|John Taylor||UUP||1986 Strangford by-election||32,627||94.2|
|Clifford Forsythe||UUP||1986 South Antrim by-election||30,087||94.1|
|William Ross||UUP||1986 East Londonderry by-election||30,922||93.9|
|Arthur Woodburn||Labour||1939 Clackmannanshire and East Stirlingshire by-election||15,645||93.7|
|Spencer Summers||Conservative||1940 Northampton by-election||16,587||93.4|
|Harry Thorneycroft||Labour||1942 Manchester Clayton by-election||8,892||93.3|
|James Hollins||Labour||1940 Silvertown by-election||14,343||92.8|
|Francis Douglas||Labour||1940 Battersea North by-election||9,947||92.6|
|Henry Willink||Conservative||1940 Croydon North by-election||14,163||90.7|
|James Henry Molyneaux||UUP||1986 Lagan Valley by-election||32,514||90.7|
Majorities over 9,000 votes overturned:
|Candidate||Party||Election||Majority overturned||New majority|
|Richard Foord||Liberal Democrats||2022 Tiverton and Honiton by-election||24,239||6,144|
|Sarah Olney||Liberal Democrats||2016 Richmond Park by-election||23,015||1,872|
|Diana Maddock||Liberal Democrats||1993 Christchurch by-election||23,015||16,427|
|Helen Morgan||Liberal Democrats||2021 North Shropshire by-election||22,949||5,925|
|Tim Smith||Conservative||1977 Ashfield by-election||22,915||264|
|Michael Carr||Liberal Democrats||1991 Ribble Valley by-election||19,528||4,601|
|Jim Sillars||SNP||1988 Glasgow Govan by-election||19,509||3,554|
|Shirley Williams||SDP||1981 Crosby by-election||19,272||5,289|
|David Bellotti||Liberal Democrats||1990 Eastbourne by-election||16,923||4,550|
|Winnie Ewing||SNP||1967 Hamilton by-election||16,576||1,799|
|Sarah Green||Liberal Democrats||2021 Chesham and Amersham by-election||16,223||8,028|
|Robin Hodgson||Conservative||1976 Walsall North by-election||15,885||4,379|
|Eric Lubbock||Liberal||1962 Orpington by-election||14,760||7,855|
|Sylvia Heal||Labour||1990 Mid Staffordshire by-election||14,654||9,449|
|John Mason||SNP||2008 Glasgow East by-election||13,507||365|
|Sarah Teather||Liberal Democrats||2003 Brent East by-election||13,047||1,118|
|Graham Tope||Liberal||1972 Sutton and Cheam by-election||12,696||7,417|
|David Rendel||Liberal Democrats||1993 Newbury by-election||12,357||22,055|
|Parmjit Singh Gill||Liberal Democrats||2004 Leicester South by-election||13,243||1,654|
|Douglas Carswell||UKIP||2014 Clacton by-election||12,068||12,404|
|David Austick||Liberal||1973 Ripon by-election||12,064||946|
|Simon Hughes||Liberal||1983 Bermondsey by-election||11,756||9,319|
|Willie Rennie||Liberal Democrats||2006 Dunfermline and West Fife by-election||11,562||1,800|
|Donald Williams||Conservative||1968 Dudley by-election||10,022||11,656|
|Mark Reckless||UKIP||2014 Rochester and Strood by-election||9,953||2,920|
Winning shares of the vote below 35%, since 1918:
|Henry Strauss||Conservative||1946 Combined English Universities by-election||5,483||30.0|
|Lisa Forbes||Labour||2019 Peterborough by-election||10,484||30.9|
|Mike Thornton||Liberal Democrats||2013 Eastleigh by-election||13,342||32.1|
|Edward Campbell||Conservative||1930 Bromley by-election||12,782||32.4|
|George Machin||Labour||1973 Dundee East by-election||14,411||32.7|
|Roy Jenkins||SDP||1982 Glasgow Hillhead by-election||10,106||33.4|
|Guy Barnett||Labour||1962 South Dorset by-election||13,783||33.5|
|James Carmichael||Ind. Labour Party||1946 Glasgow Bridgeton by-election||6,351||34.3|
|Leah Manning||Labour||1931 Islington East by-election||10,591||34.7|
|Kenneth Lindsay||National Labour||1933 Kilmarnock by-election||12,577||34.8|
|Parmjit Singh Gill||Liberal Democrats||2004 Leicester South by-election||10,274||34.9|
The 1920 Stockport by-election, was held to elect two MPs. The winners' shares of the total vote were 25.6% and 25.1%. However, as each voter could cast two votes, the situation is not readily comparable to other by-elections in this period.
At the 1909 Sheffield Attercliffe by-election, the winning candidate took only 27.5% of the vote.
Major parties winning 2% or less share of votes cast in a by-election, since 1918:
|Geoff Juby||Liberal Democrats||2014 Rochester and Strood by-election||349||0.9|
|Lee Dargue||Liberal Democrats||2022 Birmingham Erdington by-election||173||1.0|
|Stephen Arrundale||Liberal Democrats||2021 Airdrie and Shotts by-election||220||1.0|
|Andrew Hagon||Liberal Democrats||2021 Hartlepool by-election||349||1.2|
|Roger Goodfellow||Liberal||1948 Glasgow Camlachie by-election||312||1.2|
|James Scott Duckers||Liberal||1924 Westminster Abbey by-election||291||1.3|
|Andrew Graham||Liberal Democrats||2014 Clacton by-election||483||1.3|
|Hugh Annand||Liberal Democrats||2013 South Shields by-election||352||1.4|
|Robert McCreadie||Liberal Democrats||1989 Glasgow Central by-election||411||1.5|
|Natasa Pantelic||Labour||2021 Chesham and Amersham by-election||622||1.6|
|Patrick Davies||Labour||1997 Winchester by-election||944||1.7|
|Ian Miller||Liberal||1967 Glasgow Pollok by-election||735||1.9|
|Jamie Needle||Liberal Democrats||2022 Wakefield by-election||508||1.9|
|Steve Billcliffe||Labour||1993 Newbury by-election||1,151||2.0|
The worst Conservative performance was in the 1995 North Down by-election, where they took 2.1% of the votes cast.
The 'continuation' Social Democratic Party (SDP) took 0.4% of the vote at both the 1990 Upper Bann by-election and the Bootle by-election the following week.
|3||Yolande Kenward||No description||2021 North Shropshire by-election|
|5||Bill Boaks||Public Safety Democratic Monarchist White Resident||1982 Glasgow Hillhead by-election|
|5||Smiley Smilie||Independent||2016 Tooting by-election|
|5||Bobby Smith||No description||2019 Peterborough by-election|
|5||Kailash Trivedi||Independent Janata Party||1988 Kensington by-election|
|7||John Connell||Peace - stop ITN manipulation||1984 Chesterfield by-election|
|8||David Bishop||Church of the Militant Elvis Party||2022 Birmingham Erdington by-election|
|8||Esmond Bevan||Systems Designer2||1983 Bermondsey by-election|
|8||Tony Farnon||Independent||2008 Haltemprice and Howden by-election|
|8||Norman Scarth||Independent||2008 Haltemprice and Howden by-election|
|9||Bobby Smith||Bring Back Elmo||2016 Tooting by-election|
All majorities of less than 1,000 since the Second World War. Bold entries indicate a new record.
|57||1973 Berwick-upon-Tweed by-election||Liberal gain|
|62||1967 Walthamstow West by-election||Conservative gain|
|100||1986 West Derbyshire by-election||Conservative hold|
|205||1965 Leyton by-election||Conservative gain|
|219||1958 Torrington by-election||Liberal gain|
|220||1962 Central Norfolk by-election||Conservative hold|
|264||1977 Ashfield by-election||Conservative gain|
|289||1982 Birmingham Northfield by-election||Labour gain|
|293||1950 Dunbartonshire West by-election||Labour hold|
|323||2021 Batley and Spen by-election||Labour hold|
|359||1946 Combined English Universities by-election||Conservative gain|
|365||2008 Glasgow East by-election||SNP gain|
|395||1948 Glasgow Camlachie by-election||Unionist gain|
|430||1980 Southend East by-election||Conservative hold|
|437||1950 Brighouse and Spenborough by-election||Labour hold|
|452||1946 Heywood and Radcliffe by-election||Labour hold|
|460||2004 Birmingham Hodge Hill by-election||Labour hold|
|478||1969 Swindon by-election||Conservative gain|
|517||1969 Paddington North by-election||Labour hold|
|520||1977 Grimsby by-election||Labour hold|
|552||1983 Penrith and The Border by-election||Conservative hold|
|556||1999 Hamilton South by-election||Labour hold|
|557||1967 Manchester Gorton by-election||Labour hold|
|559||1985 Brecon and Radnor by-election||Liberal gain|
|571||1973 Glasgow Govan by-election||SNP gain|
|617||2014 Heywood and Middleton by-election||Labour hold|
|633||2006 Bromley and Chislehurst by-election||Conservative hold|
|641||1960 Bolton East by-election||Conservative hold|
|657||1956 Taunton by-election||Conservative hold|
|666||1960 Brighouse and Spenborough by-election||Conservative gain|
|683||2019 Peterborough by-election||Labour hold|
|704||1962 South Dorset by-election||Labour gain|
|705||2000 Falkirk West by-election||Labour hold|
|740||1968 Bassetlaw by-election||Labour hold|
|799||1986 Newcastle-under-Lyme by-election||Labour hold|
|806||1955 Mid Ulster by-election||Sinn Féin hold|
|815||1988 Kensington by-election||Conservative hold|
|822||2000 South Antrim by-election||DUP gain|
|865||1955 South Norfolk by-election||Conservative hold|
|913||1950 Belfast West by-election||UUP hold|
|917||1962 South Northamptonshire by-election||Conservative hold|
|946||1973 Ripon by-election||Liberal gain|
|971||1963 Dumfriesshire by-election||Unionist hold|
|973||1962 Blackpool North by-election||Conservative hold|
Still smaller majorities have been recorded since 1918. The majority in the 1921 Penrith and Cockermouth by-election, was only 31 votes, and in the 1924 Westminster Abbey by-election it was 43 votes, while at the 1928 Carmarthen by-election it was 47 votes. At the 1892 Cirencester by-election a majority of 3 for the Unionists was overturned on petition, where it was found that both candidates had an equal number of votes. A fresh by-election was called, which was won by the Liberals.
Turnout is the percentage of registered electors who voted.
The highest turnouts since 1918.
|1969 Mid Ulster by-election||1969||91.5%|
|1955 Mid Ulster by-election||1955||89.7%|
|1928 Ashton-under-Lyne by-election||1928||89.1%|
|1981 (August) Fermanagh and South Tyrone by-election||1981||88.6%|
|1956 Mid Ulster by-election||1956||88.4%|
|1923 Tiverton by-election||1923||88.1%|
|1926 Darlington by-election||1926||87.6%|
|1957 Carmarthen by-election||1957||87.4%|
|1981 (April) Fermanagh and South Tyrone by-election||1981||86.9%|
|1925 Stockport by-election||1925||85.7%|
|1950 Brighouse and Spenborough by-election||1950||85.4%|
It is highly unusual for a by-election to attract a higher turnout in a seat than the previous general election.
|By-election||Turnout %||Turnout %
at general election
|1936 Ross and Cromarty by-election||65.2||50.8||14.4|
|1958 Torrington by-election||80.6||69.2||11.4|
|1938 Bridgwater by-election||82.3||72.7||9.6|
|1938 Oxford by-election||76.3||67.3||9.0|
|1928 Carmarthen by-election||76.6||67.9||8.7|
|1928 St Ives by-election||77.4||69.1||8.3|
|1969 Mid Ulster by-election||91.5||83.9||7.6|
|1958 East Aberdeenshire by-election||65.9||59.8||6.1|
|1926 Kingston upon Hull Central by-election||82.8||77.1||5.7|
|1927 Bosworth by-election||84.6||80.8||3.8|
|1927 Leith by-election||73.9||70.5||3.4|
|1932 Cardiganshire by-election||70.4||67.5||2.9|
|1929 North Lanarkshire by-election||82.3||79.9||2.4|
|1957 Carmarthen by-election||87.4||85.1||2.3|
|1948 Paisley by-election||76.0||73.9||2.1|
|1967 Rhondda West by-election||82.2||80.3||1.9|
|1948 Croydon North by-election||74.8||73.2||1.6|
|1981 (August) Fermanagh and South Tyrone by-election||88.6||87.1||1.5|
|1926 Darlington by-election||87.6||86.1||1.5|
|1928 Linlithgowshire by-election||81.5||80.0||1.5|
|1973 Berwick-upon-Tweed by-election||75.0||73.7||1.3|
|1970 South Ayrshire by-election||76.3||75.1||1.2|
|1955 Mid Ulster by-election||89.7||88.6||1.1|
|1948 Wigan by-election||81.4||80.4||1.0|
|1986 Newry and Armagh by-election||76.9||76.0||0.9|
|1928 Ashton-under-Lyne by-election||89.1||88.3||0.8|
|1977 Great Grimsby by-election||70.2||69.4||0.8|
|1938 Ipswich by-election||82.8||82.1||0.7|
|1982 Glasgow Hillhead by-election||76.4||75.7||0.7|
|1938 Walsall by-election||75.9||75.2||0.7|
|1958 Argyll by-election||67.1||66.6||0.5|
|1926 Smethwick by-election||78.6||78.2||0.4|
|1967 Hamilton by-election||73.7||73.3||0.4|
|1971 Macclesfield by-election||76.6||76.4||0.2|
During the Second World War the electoral register was not kept up to date despite significant population movements, especially in the London area (which contains all three constituencies listed below). Consequently, only those eligible to vote in the constituency at the outbreak of war were eligible to vote in the by-elections and many voters were physically unable to as they were located elsewhere; in addition the major parties did not compete against each other. The lowest turnout in peacetime since 1918 was 18.2% at the 2012 Manchester Central by-election. The lowest turnouts since 1918 have been:
Turnouts of less than 30% since 1945 (bold indicates a new post-war record)
|2012 Manchester Central by-election||18.2%|
|1999 Leeds Central by-election||19.6%|
|2022 Southend West by-election||24.0%|
|1958 Shoreditch and Finsbury by-election||24.9%|
|1999 Wigan by-election||25.0%|
|2000 Tottenham by-election||25.4%|
|2012 Cardiff South and Penarth by-election||25.7%|
|2016 Batley and Spen by-election||25.8%|
|1974 Newham South by-election||25.9%|
|2012 Middlesbrough by-election||26.0%|
|2012 Croydon North by-election||26.5%|
|2022 Birmingham Erdington by-election||27.0%|
|2000 West Bromwich West by-election||27.6%|
|2011 Feltham and Heston by-election||28.8%|
|2000 Preston by-election||29.6%|
|1999 Kensington and Chelsea by-election||29.7%|
Under current UK electoral law there is no upper or lower limit for candidature numbers, with the only required stipulation being the valid nomination of ten electors from the constituency. By-elections often attract "fringe" or novelty candidates, single-issue candidates, or independents. As with nominations in a general election, candidates must pay a £500 deposit, which is only refunded if the candidate wins 5% of the votes cast.
All by-elections with more than ten candidates are listed. Elections are listed in alphabetical order. Those that created a new record number appear in bold.
In 2017, the countermanded poll in Manchester Gorton had 11 candidates.
|Year||Number of candidates||Election|
|2008||26||Haltemprice and Howden|
|1999||18||Kensington and Chelsea|
|2021||16||Batley and Spen|
|2009||13||Glasgow North East|
|2014||Rochester and Strood|
|1996||South East Staffordshire|
|1981||Croydon North West|
|2006||11||Bromley and Chislehurst|
|2021||Old Bexley and Sidcup|
|1989||Vale of Glamorgan|
|2016||10||Batley and Spen|
|1977||City of London and Westminster South|
|2008||Crewe and Nantwich|
|1995||Littleborough and Saddleworth|
|2010||Oldham East and Saddleworth|
|2016||Sleaford and North Hykeham|
|Year||Number of candidates||Election|
|1986||2||Eight of the Northern Ireland by-elections2|
|1981||Fermanagh and South Tyrone|
Former Labour cabinet minister Tony Benn contested no fewer than four by-elections during his career, topping the poll on each occasion: Bristol South East in 1950, 1961 and 1963, and Chesterfield in 1984. His first and last by-election victories were 33 years and 3 months apart.
Former cabinet minister and European Commissioner Roy Jenkins fought two different by-elections for the Social Democratic Party only eight months apart. He narrowly failed in the 1981 Warrington by-election before winning the 1982 Glasgow Hillhead by-election. He had been first elected as a Labour MP almost 34 years previously in the 1948 Southwark Central by-election.
Former Speaker of the House of Commons, Betty Boothroyd finally secured election at her third by-election attempt at the 1973 West Bromwich by-election. She had previously failed in the 1957 Leicester South East by-election and the 1968 Nelson and Colne by-election as well as the general elections of 1959 and 1970.
John Bickley of UKIP contested three by-elections (all in Greater Manchester) within two years - Wythenshawe and Sale East in February 2014, Heywood and Middleton in October 2014 and Oldham West and Royton in December 2015. He was defeated on each occasion, coming closest in Heywood and Middleton where he lost by less than 700 votes. Bickley also contested Heywood and Middleton at the 2015 general election, making a total of four parliamentary elections contested in fewer than 24 months.
Perennial fringe candidates include such personalities as Bill Boaks, whose highest vote was at the 1982 Beaconsfield by-election with 99 votes. Screaming Lord Sutch was for most of his career the leader of the Official Monster Raving Loony Party. His highest vote total was 1,114 at the 1994 Rotherham by-election. Lindi St Clair of the Corrective Party contested eleven by-elections without success, her highest total being 216 votes as 'Lady Whiplash' at the 1990 Eastbourne by-election. Sutch's successor as leader of the Official Monster Raving Loony Party, Alan "Howling Laud" Hope, has, as of the 2021 North Shropshire by-election, contested eighteen by-elections.
John Cartwright of the Official Monster Raving Loony Party has contested three by-elections without success, his most successful total being 188 at the 2007 Ealing Southall by-election. Under various ballot paper descriptions, David Bishop of the Church of the Militant Elvis label has stood at five by-elections, receiving 99 votes at the 2012 Corby by-election, an increase over his previous high of 93 at the 2011 Feltham and Heston by-election.
Arthur Henderson was distinguished in being successful in no fewer than five by-elections in different seats, in Barnard Castle, Widnes, Newcastle upon Tyne East, Burnley, and Clay Cross.
Joseph Gibbins is the only person in modern times to gain the same seat twice in two different by-elections. He triumphed for Labour in the 1924 Liverpool West Toxteth by-election and the 1935 Liverpool West Toxteth by-election.
William O'Brien won four by-elections, in Mallow in 1883, North East Cork in 1887 and then Cork City in 1904 and 1914. On these last two occasions, he was re-elected having resigned the seat.
Prime Minister Winston Churchill contested five by-elections in his long career:
John Wilkes won the 1757 Aylesbury by-election, and was then elected in the Middlesex by-elections of February, March and April 1769, on each occasion being subsequently expelled from the House of Commons.
|2012 Bradford West by-election1||George Galloway||Respect||returns after failing to win a seat in the 2010 general election|
|2000 South Antrim by-election1||William McCrea||DUP||returns after losing his Mid Ulster seat in the 1997 general election.|
|1999 Kensington and Chelsea by-election||Michael Portillo||Conservative||returns after losing his Enfield Southgate seat at the 1997 general election.|
|1997 Beckenham by-election||Jacqui Lait||Conservative||returns after losing her Hastings and Rye seat at the 1997 general election.|
|1988 Epping Forest by-election||Steve Norris||Conservative||returns after losing his Oxford East seat at the 1987 general election.|
|1988 Glasgow Govan by-election1||Jim Sillars||SNP||He had first sat as a Labour MP (later as Scottish Labour) for South Ayrshire between 1970 and 1979.|
|1984 Chesterfield by-election||Tony Benn||Labour||returns after losing his redrawn Bristol East seat at the 1983 general election.|
|1982 Beaconsfield by-election||Tim Smith||Conservative||returns after losing his Ashfield seat in the 1979 general election.|
|1982 Glasgow Hillhead by-election2:||Roy Jenkins||SDP||returns after a spell as European Commissioner, then co-founding the Social Democratic Party (SDP). He had first sat as a Labour MP for Southwark Central from 1948 to 1950 and Birmingham Stechford from 1950 to 1977.|
|1981 Crosby by-election1||Shirley Williams||SDP||returns as the first-elected SDP MP. She had first sat as a Labour MP for Hitchin 1964-74 and for Hertford and Stevenage 1974-79|
|1981 Warrington by-election||Douglas Hoyle||Labour||returns after losing his Nelson and Colne seat in the 1979 general election.|
|1980 Southend East by-election||Teddy Taylor||Conservative||returns after losing his Glasgow Cathcart seat at the 1979 general election|
|1979 South West Hertfordshire by-election||Richard Page||Conservative||returns after losing his Workington seat in the 1979 general election|
|1979 Knutsford by-election||Jock Bruce-Gardyne||Conservative||returns after losing his South Angus seat at the October 1974 general election.|
|1979 Clitheroe by-election||David Waddington||Conservative||returns after losing his Nelson and Colne seat at the October 1974 general election.|
|1978 Glasgow Garscadden by-election||Donald Dewar||Labour||returns after losing his Aberdeen South seat in the 1970 general election.|
|1977 Saffron Walden by-election||Alan Haselhurst||Conservative||returns after losing his Middleton and Prestwich seat in the February 1974 general election.|
|1974 Newham South by-election||Nigel Spearing||Labour||returns after losing his Acton seat in the February 1974 general election.|
|1972 Merthyr Tydfil by-election2||Edward Rowlands||Labour||returns after losing his Cardiff North seat in the 1970 general election.|
|1971 Greenwich by-election||Guy Barnett||Labour||returns after losing his South Dorset seat in the 1964 general election.|
|1971 Southampton Itchen by-election||Bob Mitchell||Labour||returns after losing his Southampton Test seat in the 1970 general election.|
|1970 St Marylebone by-election||Kenneth Baker||Conservative||returns after losing his Acton seat in the 1970 general election.|
|1969 Chichester by-election||Christopher Chataway||Conservative||returns after losing his Lewisham North seat in the 1966 general election.|
|1969 Brighton Pavilion by-election||Julian Amery||Conservative||returns after losing his Preston North seat in the 1966 general election.|
|1968 New Forest by-election||Patrick McNair-Wilson||Conservative||returns after losing his Lewisham West seat in the 1966 general election.|
|1968 Warwick and Leamington by-election||Dudley Smith||Conservative||returns after losing his Brentford and Chiswick seat in the 1966 general election.|
|1967 West Derbyshire by-election||James Scott-Hopkins||Conservative||returns after losing his Cornwall North seat in the 1966 general election.|
|1967 Brierley Hill by-election||Fergus Montgomery||Conservative||returns after losing his Newcastle upon Tyne East seat in the 1964 general election.|
|1967 Honiton by-election||Peter Emery||Conservative||returns after losing his Reading seat in the 1966 general election.|
|1965 Saffron Walden by-election||Peter Kirk||Conservative||returns after losing his Gravesend seat in the 1964 general election.|
|1965 Salisbury by-election||Michael Hamilton||Conservative||returns after losing his Wellingborough seat in the 1964 general election.|
|1965 East Grinstead by-election||Geoffrey Johnson-Smith||Conservative||returns after losing his Holborn and St. Pancras South seat in the 1964 general election.|
|1965 Altrincham and Sale by-election||Anthony Barber||Conservative||returns after losing his Doncaster seat in the 1964 general election.|
|1963 St Marylebone by-election||Quintin Hogg||Conservative||returns after disclaiming his peerage. He had previously sat for Oxford 1938–1950.|
|1963 Kinross and Western Perthshire by-election||Sir Alec Douglas-Home||Unionist||returns after disclaiming his peerage. He had previously sat for Lanark 1931-45 and 1950–51.|
|1963 Bristol South East by-election||Tony Benn||Labour||returns after disclaiming his peerage. He had been disqualified after the death of his father in 1960, and his election in a 1961 by-election had been adjudged undue on petition.|
|1962 Middlesbrough East by-election||Arthur Bottomley||Labour||returns after losing his Rochester and Chatham seat in the 1959 general election.|
|1960 Ebbw Vale by-election||Michael Foot||Labour||returns after losing his Plymouth Devonport seat in the 1955 general election.|
|1956 Newport by-election||Frank Soskice||Labour||returns after his Sheffield Neepsend seat was abolished at the 1955 general election.|
|1950 Sheffield Neepsend by-election||Frank Soskice||Labour||returns after his Birkenhead East seat was abolished at the 1950 general election.|
|1913 Houghton-le-Spring by-election1||Thomas Edward Wing||Liberal||returns after losing his Grimsby seat at the December 1910 general election.|
|1911 Bootle by-election||Bonar Law||Conservative||returns after failing to win Manchester North-West in the December 1910 general election.|
|1908 Dundee by-election||Winston Churchill||Liberal||returns after losing his Manchester North West seat in a 1908 by-election, upon his appointment to the Board of Trade.|
|1906 Dulwich by-election||Bonar Law||Conservative||returns after losing his Glasgow Blackfriars and Hutchesontown seat in the 1906 general election.|
|February 1906 City of London by-election||Arthur Balfour||Conservative||returns after losing his Manchester East seat in the 1906 general election.|
1 by-election gain lost at the subsequent general election
2 by-election gain held at the subsequent general election
Until the Re-election of Ministers Acts 1919 and 1926 there were many cases of members having to seek re-election on appointment to ministerial office. In eight instances they were unsuccessful:
Note this list covers completed service only; it excludes any current MPs.
|Member of Parliament||By-election||Party||Duration (days)|
|Bobby Sands||1981 (April) Fermanagh and South Tyrone by-election||Anti H-Block||251|
|Michael Carr||1990 (May) Bootle by-election||Labour||571|
|Oswald O'Brien||1983 Darlington by-election||772|
|Margo MacDonald||1973 Glasgow Govan by-election||SNP||922|
|Jane Dodds||2019 Brecon and Radnorshire by-election||Liberal Democrats||972|
|Charles Beattie||1955 Mid Ulster by-election||UUP||1233|
|Mark Reckless||2014 Rochester and Strood by-election||UKIP||1302b|
|Lisa Forbes||2019 Peterborough by-election||Labour||1532|
|Sarah Olney||2016 Richmond Park by-election||Liberal Democrats||1532a|
|Nicol Stephen||1991 Kincardine and Deeside by-election||1542|
|Ashok Kumar||1991 Langbaurgh by-election||Labour||1542a|
|Helen McElhone||1982 Glasgow Queen's Park by-election||1894|
|David Austick||1973 Ripon by-election||Liberal||2172|
|John Spellar||1982 Birmingham Northfield by-election||Labour||2242a|
|Christopher Ward||1969 Swindon by-election||Conservative||2312|
|William McCrea||2000 South Antrim by-election||DUP||2592ab|
|Parmjit Singh Gill||2004 Leicester South by-election||Liberal Democrats||2942|
|David Colville Anderson||1963 Dumfriesshire by-election||Unionist||3095|
|Huw Edwards||1991 Monmouth by-election||Labour||3292a|
|Thomas Teevan||1950 Belfast West by-election||UUP||3302|
|Wallace Lawler||1969 Birmingham Ladywood by-election||Liberal||3572|
|George Machin||1973 Dundee East by-election||Labour||3642|
See Baby of the House of Commons
Debuts in Parliament:
Comebacks to Parliament:
In defence of a previously held seat:
The first woman to be elected in a by-election was Nancy Astor, who succeeded her husband at the 1919 Plymouth Sutton by-election, becoming the first woman to take her seat in the House of Commons.
The first woman to gain a seat in a by-election was Susan Lawrence who won the 1926 East Ham North by-election, although she had previously sat for the same seat between 1923 and 1924.1
The first woman to gain a seat ab initio in a by-election was Jennie Lee who won the 1929 North Lanarkshire by-election, at the same time becoming the first woman Baby of the House of Commons.
Note 1 Mabel Philipson succeeded her husband at the 1923 Berwick-upon-Tweed by-election. He had been elected as a National Liberal Party candidate. She won as a Conservative so this could arguably be classed as the first gain by a woman.
Whilst the first ethnic minority Members of Parliament were elected at general elections as early as the 1890s, it would be almost 100 years before one was returned at a by-election.
The first ethnic minority candidate to be elected in a by-election was Ashok Kumar who gained the 1991 Langbaurgh by-election for Labour.
The first by-election in which all three major-party candidates were from the ethnic minorities was the 2007 Ealing Southall by-election, held by Labour.
When the UK Parliament was established in 1801, non-Anglicans were prevented from taking their seats as MPs under the Test Act 1672. However, Methodists took communion at Anglican churches until 1795, and some continued to do so, and many Presbyterians were prepared to accept Anglican communion, thus ensuring that members of these creeds were represented in the Parliament. Some Unitarians were also elected.
The first by-election victor (and first ever MP) to be an adherent of the Eastern Orthodox Church was The Honourable Frederick North who was elected in 1792 for Banbury (to succeed his brother who had entered the House of Lords), having converted to the faith the previous year.
The first Roman Catholic by-election victor in the UK Parliament was Daniel O'Connell in the 1828 Clare by-election. He was not permitted to take his seat until the following year.
The first atheist by-election victor was Charles Bradlaugh, at the 1881 Northampton by-election. As an atheist, Bradlaugh was not allowed to swear the Oath of Allegiance, and the by-election was re-run in 1882 and 1884. Both were also won by Bradlaugh, who eventually was able to take his seat after the 1885 general election.
Most physically disabled MPs in the history of the parliament entered in the intakes of general elections. Those known to have been disabled when entering parliament at by-elections are rarer and include:
1Hilton Dawson, Thelma Walker, and Paul Williams 2 Conservative MPs David Davis and Walter Sweeney
The years 1998 and 2020 stand as the two in modern British history without any Westminster election. 1992, 1998, 2010 and 2020 are the four full calendar years in history without a single by-election.
|1 August 2019||6 May 2021||645|
|20 November 1997||10 June 1999||567|
|7 November 1991||6 May 1993||546|
|12 March 1987||14 July 1988||489|
|14 February 2002||18 June 2003||483|
|23 February 2017||3 May 2018||434|
|12 November 2009||13 January 2011||427|
|23 May 1974||26 June 1975||399|
|18 June 2003||15 July 2004||393|
|29 June 2006||19 July 2007||385|
The longest period without a seat changing hands in a by-election was the five years between the Conservative victories in the 1948 Glasgow Camlachie by-election and the 1953 Sunderland South by-election.
During the short Parliaments of 1910, 1950-1 and 1974 no seats changed hands in a by-election.
The Liberal Party endured 29 years without a single by-election gain between the 1929 Holland with Boston by-election and the 1958 Torrington by-election. It did not win a single by-election in the thirteen years between holding the 1945 Middlesbrough West by-election and gaining Torrington.
Until the 2008 Crewe and Nantwich by-election, the opposition Conservative Party had not gained a seat in almost 26 years, the last being the 1982 Mitcham and Morden by-election, which occurred during the unique circumstances of the Falklands War and the sitting Labour MP defecting to the Social Democratic Party and seeking re-election under his new party label. The Conservatives' last gain while in Opposition was 30 years previously at the 1978 Ilford North by-election.
Labour's longest lean stretch was almost 18 years, between gaining the 1939 Brecon and Radnorshire by-election and the 1957 Lewisham North by-election.1
As of 18 July 2022, the most recent gains for each currently active party were:
|Labour||23 June 2022||25 days||Wakefield||Gain from||Conservative|
|Liberal Democrats||23 June 2022||25 days||Tiverton and Honiton||Gain from||Conservative|
|Conservative||6 May 2021||1 year, 2 months and 12 days||Hartlepool||Gain from||Labour|
|UKIP||20 November 2014||7 years, 7 months and 28 days||Rochester and Strood2||Gain from||Conservative|
|SNP||24 July 2008||13 years, 11 months and 24 days||Glasgow East||Gain from||Labour|
|DUP||27 April 2000||22 years, 2 months and 21 days||South Antrim||Gain from||UUP|
|SDLP||23 January 1986||36 years, 5 months and 25 days||Newry and Armagh||Gain from||UUP|
|Plaid Cymru||14 July 1966||56 years and 4 days||Carmarthen||Gain from||Labour|
|UUP||6 June 1946||76 years, 1 month and 12 days||Down3||Gain from||Independent|
|Sinn Féin||20 June 1918||104 years and 28 days||East Cavan4||Gain from||Irish Parliamentary|
1 The Labour Party were the official opposition in the Parliament elected in 1935, but after the major parties agreed an electoral truce on the outbreak of war in 1939, they did not contest any Conservative or Liberal seats for the remainder of the Parliament, a period of six years, and were members of the wartime coalition government between May 1940 and May 1945.
2 Notional gain: incumbent Conservative stood as UKIP. No UKIP candidate has ever defeated an incumbent of a different party
3 The UUP were also declared winners of the 1955 Mid Ulster by-election after the Sinn Féin candidate was disqualified, but the UUP candidate was also disqualified shortly after.
4 Sinn Féin have not gained a seat at a by-election since 1918. However, the Anti H-Block party, an Irish Republican group that merged into Sinn Féin, gained Fermanagh and South Tyrone in the April 1981 by-election (41 years, 3 months and 9 days ago).
The Conservatives did not successfully defend a single by-election in the eight years between their holds of the 1989 Richmond (Yorks) by-election and the 1997 Uxbridge by-election, losing a record 15 consecutive seats where they were the incumbents. By the time of the by-election in Uxbridge, the victor in Richmond, William Hague, had become leader of the Conservative Party.
Labour's worst run was 4 consecutive by-election losses, which has occurred three times since 1945:
Between the 1988 Glasgow Govan by-election and the 2003 Brent East by-election, Labour successfully defended every seat it held at by-elections, for a total of 30 holds (not counting Falkirk West and West Bromwich West, represented by a Labour MP turned independent and a Labour speaker respectively and both won by Labour). The span of 14 years, 10 months and 8 days is the longest period without a by-election defeat for either of the two main parties. The Conservatives did not lose a seat between the 2000 Romsey by-election and the 2012 Corby by-election, a span of 12 years, 6 months and 12 days. However, they only defended 3 seats in that time. In terms of total number, their longest run of by-election holds was 51, between the 1945 Chelmsford by-election and the 1957 Lewisham North by-election, a span of 11 years, 9 months and 21 days.
Since their formation, the Liberal Democrats have held every Lib Dem seat contested at a by-election, of which there have been 3. Including their successor parties, their most recent by-election loss was the 1982 Mitcham and Morden by-election, lost by the SDP 40 years, 1 month and 15 days ago. The SDP candidate had however defected from Labour – the last seat lost by either party that had been won at a previous election was the 1957 Carmarthen by-election, lost by the Liberals 65 years, 4 months and 20 days ago. Since 1982, the Liberal Democrats and predecessors together have defended 4; since 1957 they have defended 5 seats.
By-elections in seats held by minor and nationalist parties are rare, and so most have never lost a seat – the DUP and Plaid Cymru have defended but never lost a seat at a by-election, Sinn Féin have only lost seats by disqualification, and the UUP have never lost more than one seat in a row. No by-election has ever been called in an SDLP held seat.
For a period of 11 years, until the 2008 Crewe and Nantwich by-election, the principal opposition Conservative Party failed to register a by-election gain against the incumbent Labour Government. This is the longest period of such failure since records began, and more than twice the previous record of the five years it took the then Labour opposition to gain the 1957 Lewisham North by-election. The present Labour opposition did not register a gain for over nine years, between the 2012 Corby by-election and the 2022 Wakefield by-election
Apart from the brief parliaments of 1910, 1950-1 and 1974, the parliaments of 1951-5 and 1997-2001 are the only occasions when the Government did not lose a by-election.
The largest number of by-elections held on a single day occurred on 23 January 1986 when 15 simultaneous contests were held in Northern Ireland. The elections had been engineered by the incumbent Unionist parties as a protest against the Anglo-Irish Agreement of 1985. They intended the results to be interpreted as a referendum on the treaty. The elections were boycotted by the main Nationalist parties except in four seats where they had a reasonable prospect of victory. In the event, the Social Democratic and Labour Party gained one seat, Newry and Armagh, from the Ulster Unionist Party.
Apart from the above example, it is common for UK mainland parties to schedule several by-elections on the same day. Motivations include attempting to divide opponents' resources and getting bad news (expected losses) out of the way. Since 1945, the largest number of simultaneous mainland by-elections has been 6, held on 16 November 1960. On four occasions, 5 by-elections have been held on the same day, most recently on 9 June 1994. Groupings of two or three are very common.
Before November 2012, the last day on which three by-elections had been held was 23 November 2000. In November 2012 there were two such groupings of three (15 November and 29 November). The last time there were six by-elections in one calendar month was in June 1994.
The largest number of by-elections lost on a single day is three, when the Labour party lost Acton, Dudley and Meriden on 28 March 1968, all to the Conservatives.
Occasions since 1945 when two seats have fallen are:
|Date||By-election||Winning party||Losing party|
|23 June 2022||2022 Tiverton and Honiton by-election||Liberal Democrats||Conservative|
|2022 Wakefield by-election||Labour|
|7 November 1991||1991 Kincardine and Deeside by-election||Liberal Democrats|
|1991 Langbaurgh by-election||Labour|
|4 November 1976||1976 Walsall North by-election||Conservative||Labour|
|1976 Workington by-election|
|8 November 1973||1973 Glasgow Govan by-election||SNP|
|1973 Berwick-upon-Tweed by-election||Liberal||Conservative|
|26 July 1973||1973 Ripon by-election|
|1973 Isle of Ely by-election|
|2 November 1967||1967 Hamilton by-election||SNP||Labour|
|1967 Leicester South West by-election||Conservative|
|21 September 1967||1967 Walthamstow West by-election|
|1967 Cambridge by-election|
|22 November 1962||1962 Glasgow Woodside by-election||Labour||Conservative|
|1962 South Dorset by-election|
British Parliamentary elections are invariably held on a Thursday. The last by-election not held on a Thursday was the 1978 Hamilton by-election, held on Wednesday 31 May due to a World Cup opening match on the Thursday evening.
Due to an administrative oversight, the 1973 Manchester Exchange by-election was held on Wednesday 27 June 1973. Prior to that, the last by-elections not held on a Thursday were the 1965 Saffron Walden by-election held on Tuesday 23 March, and the 1965 Roxburgh, Selkirk and Peebles by-election held the following day.
Until the mid-1960s, it was common to hold by-elections on any day of the week (other than Sunday).
Very occasionally, a scheduled by-election may be overtaken by the calling of a general election and the dissolution of Parliament, in which case the poll is countermanded by the Returning Officer. There have been only three occasions since 1918: a by-election was scheduled to take place in Warwick and Leamington on 21 November 1923, but was cancelled by a dissolution of Parliament on 16 November. A by-election was scheduled to poll between 13 and 17 October 1924 in London University but was cancelled by a dissolution of Parliament on 9 October. In 2017 the Manchester Gorton by-election was cancelled by a Motion in the House of Commons following the calling of the 2017 United Kingdom general election.
Occasionally seats are left vacant for a substantial period.
No by-election writ was moved for any seat held by Sinn Féin after the 1918 general election. Four Sinn Féin candidates were elected in two different seats and would have had to decline one of them if they had wanted to take their seats. They were Éamon de Valera (East Clare and East Mayo), Arthur Griffith (East Cavan and North West Tyrone), Eoin MacNeill (Londonderry City and National University of Ireland) and Liam Mellowes (East Galway and North Meath).
By the end of the Parliament, the following Sinn Féin MPs had died without being replaced: Pierce McCan (East Tipperary) of influenza on 6 March 1919, Terence MacSwiney (Mid Cork) following a hunger strike in Brixton prison on 25 October 1920, Frank Lawless (North County Dublin) as a result of a riding injury on 16 April 1922, Joseph McGuinness (Longford) on 31 May 1922, Cathal Brugha (Waterford) in action during the Irish Civil War on 7 July 1922, Harry Boland (South Roscommon) shot while being arrested on 2 August 1922, Arthur Griffith (East Cavan and North West Tyrone) on 12 August 1922, and Michael Collins (South Cork assassinated on 22 August 1922). In each case their seats were abolished in 1922 as a result of the establishment of the Irish Free State.
Other than these cases the longest time a seat has been left vacant with no by-election held is when Dennis Vosper was elevated to the Peerage on 20 April 1964, and no writ was moved by the time Parliament was dissolved on 25 September 1964.
|Date of assassination||Member||Detail||By-election||By-election date||Defending party||Winning party|
|15 October 2021||Sir David Amess||Stabbed during a surgery by an Islamic extremist||2022 Southend West by-election||3 February 2022||Conservative||Conservative|
|16 June 2016||Jo Cox||Cox was killed by a white nationalist||2016 Batley and Spen by-election||20 October 2016||Labour||Labour|
|30 July 1990||Ian Gow||Killed by Provisional IRA bomb under his car||1990 Eastbourne by-election||18 October 1990||Conservative||Liberal Democrats|
|12 October 1984||Sir Anthony Berry||Killed by Provisional IRA bombing of Brighton||1984 Enfield Southgate by-election||13 December 1984||Conservative||Conservative|
|14 November 1981||Rev. Robert Bradford||Shot by Provisional IRA||1982 Belfast South by-election||4 March 1982||UUP||UUP|
|22 June 1922||Field Marshal Sir Henry Wilson, Bt.||Shot outside his home by IRA gunmen||July 1922 North Down by-election||21 July 1922||UUP||UUP|
|Member||By-election||By-election date||Defending Party||Winning Party|
|Gordon McMaster||1997 Paisley South by-election||6 November 1997||Labour||Labour|
|John Heddle||1990 Mid Staffordshire by-election||22 March 1990||Conservative||Labour|
|Jocelyn Cadbury||1982 Birmingham Northfield by-election||28 October 1982||Conservative||Labour|
|Bobby Sands1||1981 (August) Fermanagh and South Tyrone by-election||20 August 1981||Anti H-Block||Anti H-Block|
|Bernard Floud||1968 Acton by-election||28 March 1968||Labour||Conservative|
|Sir Albert Braithwaite||1960 Harrow West by-election||17 March 1960||Conservative||Conservative|
|Thomas Stamford||1949 Leeds West by-election||21 July 1949||Labour||Labour|
|John Whittaker||1946 Heywood and Radcliffe by-election||21 February 1946||Labour||Labour|
|Sir Charles Cayzer||1940 City of Chester by-election||7 March 1940||Conservative||Conservative|
|Anthony Muirhead||1939 Wells by-election||13 December 1939||Conservative||Conservative|
|Edward Marjoribanks||1932 Eastbourne by-election||28 April 1932||Conservative||Conservative|
By-elections are ostensibly to vote for a 'person', not a 'party', meaning that a member switching parties mid-term is not cause for a by-election. However, some members do seek re-election under their new party as a point of principle.
|Member of Parliament||By-election||Former party||New party||Details|
|Stephen Phillips||2016 Sleaford and North Hykeham by-election||Conservative||Did not contest||Resigned, citing irreconcilable differences with his party owing to a "lurch to the right", he could no longer accept the appellation "Conservative" or continue to represent his constituents.|
|Mark Reckless||2014 Rochester and Strood by-election||Conservative||UKIP||Joined the UK Independence Party over policy on European Union membership referendum.|
|Douglas Carswell||2014 Clacton by-election||Conservative||UKIP||Joined the UK Independence Party over policy on European Union membership referendum.|
|Robert Mellish||1983 Bermondsey by-election||Labour||Did not contest||Disenchanted with left-wing takeover of his Constituency Labour Party (CLP), obtained a job with the London Docklands Development Corporation, left the Labour Party and resigned to force a by-election.|
|Bruce Douglas-Mann||1982 Mitcham and Morden by-election||Labour||SDP||Sought re-election having defected to newly formed SDP; defeated by Conservative candidate.|
|Dick Taverne||1973 Lincoln by-election||Labour||Democratic Labour||Sought re-election as an Independent 'Democratic Labour' candidate after being deselected by his CLP; he was successful.|
|Ray Gunter||1972 Southwark by-election||Labour||Did not contest||Resigned from the Labour Party in disagreement with its stance opposing European Economic Community entry.|
|Victor Raikes||1957 Liverpool Garston by-election||Conservative||Did not contest||Resigned the Conservative whip over the Suez crisis, and then resigned from Parliament on obtaining a business appointment in Southern Rhodesia.|
|Stanley Evans||1957 Wednesbury by-election||Labour||Did not contest||Supported the Conservative government's Suez policy, resigned after being asked to by his Constituency Labour Party.|
|Anthony Nutting||1956 Melton by-election||Conservative||Did not contest||Minister of State for Foreign Affairs, resigned in protest at Suez invasion policy.|
|William Allen Jowitt||1929 Preston by-election||Liberal||Labour||Sought re-election as Labour Party candidate having been offered role of Attorney General by Ramsay MacDonald.|
|Joseph Kenworthy||1926 Kingston upon Hull Central by-election||Liberal||Labour||Sought re-election as Labour Party candidate following disillusion with leadership of Lloyd George.|
|J. E. B. Seely||1904 Isle of Wight by-election||Conservative||Independent||Resigned seat in opposition to Conservative policy. Returned unopposed as an independent Conservative and subsequently re-elected in 1906 as a Liberal MP.|
|Cathcart Wason||1902 Orkney and Shetland by-election||Liberal||Independent||Resigned and successfully re-contested his seat|
Main article: List of UK Parliamentary election petitions
These records show the rare occasions when the government won a seat they had not won at the previous general election.
|Conservative||2021 Hartlepool by-election||Labour|
|2017 Copeland by-election|
|1982 Mitcham and Morden by-election|
|1961 Bristol South-East by-election1|
|1960 Brighouse and Spenborough by-election|
|1953 Sunderland South by-election|
|1926 Combined English Universities by-election||Liberal|
|1923 Berwick-upon-Tweed by-election3||National Liberal|
|1922 Hackney South by-electionb||Independent|
|1921 Woolwich East by-electionb||Labour|
|1920 Stockport by-election2b||Coalition Labour|
|Laboura||1929 Liverpool Scotland by-election4||Irish Nationalist|
|1929 Preston by-election5||Liberal|
|1924 Liverpool West Toxteth by-election||Conservative|
|Liberal||1913 Chesterfield by-election||Labour|
|1913 Londonderry City by-election||Irish Unionist|
|1912 Hanley by-election||Labour|
|1912 Hackney South by-election||Independent|
These records show the rare occasions when the official Opposition failed to hold on to a seat they had won at the previous General election.
|Lost by||Gained by||By-election|
|Conservative||Liberal Democrats||2000 Romsey by-election|
|Unity||1969 Mid Ulster by-election (from Ulster Unionist)|
|Liberal||1965 Roxburgh, Selkirk and Peebles by-election|
|Empire Crusade||1930 Paddington South by-election1|
|Labour||1924 Liverpool West Toxteth by-election|
|Labour||Conservative||2021 Hartlepool by-election|
|2017 Copeland by-election|
|Respect||2012 Bradford West by-election|
|SNP||1988 Glasgow Govan by-election|
|SDP||1987 Greenwich by-election|
|Liberal||1983 Bermondsey by-election|
|Conservative||1982 Mitcham and Morden by-election|
|SNP||1973 Glasgow Govan by-election|
|Democratic Labour||1973 Lincoln by-election|
|Liberal||1972 Rochdale by-election|
|Conservative||1961 Bristol South East by-election2|
|Conservative||1960 Brighouse and Spenborough by-election|
|Conservative||1953 Sunderland South by-election|
|Liberal||1927 Southwark North by-election|
|Liberal||1923 Anglesey by-election3|
|Unionist||1921 Woolwich East by-election4|
On rare occasions a party has failed to overturn an incumbent in the by-election yet has gone on to gain the seat at the subsequent general election.
|By-election||Held by||Gain by||General election|
|2019 Peterborough by-election||Labour||Conservative||2019|
|2013 Eastleigh by-election||Liberal Democrats||Conservative||2015|
|2011 Inverclyde by-election||Labour||SNP||2015|
|2006 Blaenau Gwent by-election||Independent||Labour||2010|
|1986 South Down by-election||UUP||SDLP||1987|
|1983 Darlington by-election||Labour||Conservative||1983|
|1973 Dundee East by-election||Labour||SNP||February 1974|
|1960 Bolton East by-election||Conservative||Labour||1964|
|1928 Carmarthen by-election||Liberal||Labour||1929|
|1905 New Forest by-election||Conservative||Liberal||1906|
It is unusual for a political party which has not contested a seat at a general election to take it at a subsequent by-election. Independent candidates are not included.
|By-election||Gain by||Majority percentage|
|2014 Rochester and Strood by-election||UKIP4||7.3|
|2014 Clacton by-election||UKIP4||35.1|
|2000 South Antrim by-election||DUP||2.7|
|1995 North Down by-election||UK Unionist||10.6|
|1982 Glasgow Hillhead by-election||SDP1||6.8|
|1981 Crosby by-election||SDP1||9.2|
|April 1981 Fermanagh and South Tyrone by-election||Anti H-Block||2.4|
|1973 Isle of Ely by-election||Liberal||3.3|
|1973 Lincoln by-election||Democratic Labour2||35.0|
|1969 Mid Ulster by-election||Unity||6.6|
|1967 Hamilton by-election||SNP||4.5|
|1958 Torrington by-election||Liberal||0.6|
|1945 Chelmsford by-election||Common Wealth||15.0|
|1945 Motherwell by-election||SNP||2.8|
|1944 Skipton by-election||Common Wealth||12.4|
|1943 Eddisbury by-election||Common Wealth||2.7|
|1943 Belfast West by-election||NI Labour||12.8|
|1936 Ross and Cromarty by-election||National Labour||16.5|
|1936 Combined Scottish Universities by-election||National Labour||25.3|
|1934 Merthyr by-election||Labour||23.0|
|1930 Paddington South by-election||Empire Crusade||4.7|
|1929 Liverpool Scotland by-election||Labour||unopposed|
|1926 Kingston upon Hull Central by-election||Labour||15.3|
|1921 Kirkcaldy Burghs by-election||Labour||6.8|
|1921 Woolwich East by-election||Unionist3||2.6|
In addition to the above section, other minor party successes include the following. For a complete list, see the list of UK minor party and independent MPs elected.
|George Galloway||Respect||2012 Bradford West by-election||18,341||52.8|
|Dai Davies||Independent||2006 Blaenau Gwent by-election||12,543||46.7|
|James Kilfedder||UPUP||1986 North Down by-election||30,793||79.2|
|Owen Carron||Anti H-Block||1981 (August) Fermanagh and South Tyrone by-election||31,278||49.1|
|George Forrest||Ind U||1956 Mid Ulster by-election||28,605||48.4|
|James Carmichael||Ind. Labour Party||1946 Glasgow Bridgeton by-election||6,351||34.3|
Labour joined the Liberal Democrats and the Greens in not contesting the 2022 Southend West by-election, out of respect following the murder of the previous MP, Sir David Amess.
The Conservatives declined to run a candidate in the 2016 Richmond Park by-election, instead backing Conservative incumbent Zac Goldsmith, who was designated as an Independent.
The Conservatives, Liberal Democrats, UKIP, and Green Party declined to run candidates in the 2016 Batley and Spen by-election, due to the circumstances regarding the killing of the previous MP, Jo Cox.
Neither the Liberal Democrat nor the Labour Party stood candidates in the 2008 Haltemprice and Howden by-election. The by-election was a single-issue election in regards to government security policy, in which the Liberal Democrats supported the Conservative candidate.
The Conservative Party did not run a candidate in the 1963 Bristol South East by-election, the 1957 Carmarthen by-election, the 1948 Paisley by-election or the 1946 Ogmore by-election.
The Labour Party did not run in the 1945 City of London by-election, the 1945 Kensington South by-election or the 1946 Combined English Universities by-election.
Prior to 2008, the last by-election without an official Liberal Democrat, Liberal or SDP candidate had been the 1994 Newham North East by-election; the Lib Dems nominated a candidate, but he joined the Labour Party before the election. No official Liberal candidate was nominated for the 1980 Glasgow Central by-election, whilst no Liberal stood in either the 1973 Westhoughton by-election or the 1973 West Bromwich by-election, both held on 24 May 1973.
The last Scottish by-elections without official Scottish National Party candidates were the 1965 Roxburgh, Selkirk and Peebles by-election and the 1964 Rutherglen by-election.
Plaid Cymru did not stand a candidate for the 2019 Brecon and Radnorshire by-election, choosing instead to endorse the Liberal Democrat candidate in a "Stop Brexit" alliance. Prior to that, the last Welsh by-elections without official Welsh Nationalist candidates were the 1950 Abertillery by-election, the 1946 Pontypool by-election and the 1945 Monmouth by-election.
The more fluid nature of politics in Northern Ireland makes it harder to define all major parties. In addition many by-elections have not been contested by parties holding other seats in the House of Commons, whether due to agreements with other parties, poor organisation in the constituency or the particular circumstances on the by-election. However, for the period since 1981 (which saw the first by-elections in twelve years, during which time several major political realignments had occurred) the main parties are usually considered to be the Democratic Unionist Party, Sinn Féin, the Social Democratic and Labour Party (SDLP) and the Ulster Unionist Party.
At the 2013 Mid Ulster by-election. a single "unity" candidate was backed by the withdrawal of the Democratic Unionist Party, Ulster Conservatives and Unionists and Traditional Unionist Voice. Prior to Mid Ulster in 2013, the most recent examples of by-elections without official Democratic Unionist candidates were the 1995 North Down by-election and the 1990 Upper Bann by-election. They also did not stand in the twelve seats held by other Unionist parties in the 15 by-elections in 1986.
The last by-election without official candidates from either Sinn Féin or the SDLP was the 1995 North Down by-election. Both parties also declined to stand in the eleven Unionist majority seats in the 15 by-elections in 1986. The SDLP also did not contest either the April or August 1981 by-elections in Fermanagh and South Tyrone.
The last by-elections without official Ulster Unionist candidates prior to Mid Ulster in 2013 were North Antrim, East Belfast, Mid Ulster and North Down in the 15 by-elections in 1986.
The main British parties have generally not stood in seats in Northern Ireland. The by-election exceptions are the 1990 Upper Bann by-election (NI Conservatives and continuing SDP) and the 1995 North Down by-election (NI Conservatives). Prior to the 1970s the Ulster Unionists were effectively the local Conservatives, whilst the Liberals contested some but not all seats. The SDLP has traditionally seen itself as a "sister party" to the British Labour party, and its MPs usually accept the Labour whip in Parliament.
Parties without representation in the House of Commons which saved their deposit:
|Alliance||1986 Belfast East by-election||Oliver Napier||5,917||17.4||2||Party historically represented at Westminster|
|Alliance||1986 Belfast North by-election||Paul Maguire||5,072||16.7||2||Party historically represented at Westminster|
|Alliance||1982 Belfast South by-election||David Cook||11,726||26.9||2||Party historically represented at Westminster|
|Alliance||1986 Belfast South by-election||David Cook||7,635||25.0||2||Party historically represented at Westminster|
|Alliance||1986 East Antrim by-election||Seán Neeson||5,405||15.1||2||Party historically represented at Westminster|
|Alliance||1986 North Down by-election||John Cushnahan||8,066||20.8||2||Party historically represented at Westminster|
|Alliance||1995 North Down by-election||Oliver Napier||6,970||25.4||3||Party historically represented at Westminster|
|Alliance||2000 South Antrim by-election||David Ford||2,031||6.6||5||Party represented in the Northern Ireland Assembly and historically at Westminster|
|All Party Alliance||1968 Oldham West by-election||John Creasey||3,389||13.2||3|
|Brexit Party||2019 Peterborough by-election||Mike Greene||9,801||28.9||2||Party represented in the European Parliament|
|Brexit Party||2019 Brecon and Radnorshire by-election||Des Parkinson||3,331||10.5||3||Party represented in the European Parliament|
|BNP||1994 Dagenham by-election||John Tyndall||1,511||7.0||4|
|BNP||2011 Barnsley Central by-election||Enis Dalton||1,463||6.0||4||Party represented in the European Parliament|
|BNP||2007 Sedgefield by-election||Andrew Spence||2,494||8.9||4|
|BNP||2012 Rotherham by-election||Marlene Guest||1,804||8.5||3||Party represented in the European Parliament|
|English Democrat||2008 Haltemprice and Howden by-election||Joanne Robinson||1,714||7.2||3|
|Green||2008 Haltemprice and Howden by-election||Shan Oakes||1,758||7.4||2||Party represented in the European Parliament and subsequently at Westminster|
|Green||2009 Norwich North by-election||Rupert Read||3,350||9.7||5||Party represented in the European Parliament and subsequently at Westminster|
|Green||1989 Vauxhall by-election||Henry Bewley||1,767||6.1||4||Party represented in the House of Lords|
|Independent||2013 Mid Ulster by-election||Nigel Lutton||12,781||34.4||2||DUP, UUP and TUV did not stand candidates and supported Lutton's candidacy|
|Independent||1946 Combined English Universities by-election||Mary Stocks||5,124||28.0||2|
|Independent||1946 Combined English Universities by-election||Ernest Simon||4,028||22.0||3|
|Independent||2021 Hartlepool by-election||Sam Lee||2,904||9.7||3|
|Independent||2022 Wakefield by-election||Akef Akbar||2,090||7.7||2|
|Independent||1986 East Londonderry by-election||Peter Barry||2,001||6.1||2||Fictitious paper candidate running as "For the Anglo-Irish Agreement"|
|Independent||2013 South Shields by-election||Ahmed Khan||1,331||5.4||4|
|Independent||2011 Barnsley Central by-election||Tony Devoy||1,266||5.2||5|
|Independent||1999 Hamilton South by-election||Stephen Mungall||1,075||5.5||5|
|Independent||2007 Sedgefield by-election||Paul Gittins||1,885||6.7||5|
|Independent||1986 South Antrim by-election||Peter Barry||1,870||5.9||2||Fictitious paper candidate running as "For the Anglo-Irish Agreement"|
|Independent||1986 Strangford by-election||Peter Barry||1,993||5.8||2||Fictitious paper candidate running as "For the Anglo-Irish Agreement"|
|Independent Labour||1946 Combined English Universities by-election||S. Wormald||3,414||18.7||4|
|Independent Labour||1991 Liverpool Walton by-election||Lesley Mahmood||2,613||6.5||3|
|Ind U||1946 Down by-election||J. Hastings-Little||16,895||17.1||3|
|Ind U||1995 North Down by-election||Alan Chambers||2,170||7.9||4|
|Anti-Partition||1948 Armagh by-election||James O'Reilly||16,284||40.3||2||Party later represented at Westminster|
|Irish Labour||1950 Belfast West by-election||Jack Beattie||30,833||49.2||2||Party previously and later represented at Westminster|
|Lincolnshire Independent||2016 Sleaford and North Hykeham by-election||Marianne Overton||2,892||8.8||5|
|National Fellowship||1963 Bristol South East by-election||Edward Martell||4,834||19.0||2|
|National Front||1973 West Bromwich by-election||Martin Webster||4,789||16.0||3|
|NI Labour||1959 Belfast East by-election||James Gardner||14,264||42.2||2||Party represented in the Parliament of Northern Ireland and previously at Westminster|
|NI Labour||1952 Belfast South by-election||Samuel Napier||7,655||24.9||2||Party previously represented at Westminster|
|NI Labour||1963 Belfast South by-election||Norman Searight||7,209||25.8||2||Party represented in the Parliament of Northern Ireland and previously at Westminster|
|NI Labour||1946 Down by-election||Desmond Donnelly||28,846||29.3||2||Party represented in the Parliament of Northern Ireland and previously at Westminster|
|Peace||2012 Middlesbrough by-election||Imdad Hussain||1,060||6.3||5|
|Plaid Cymru||1946 Aberdare by-election||Wynne Samuel||7,090||20.0||2||Party later represented at Westminster|
|Plaid Cymru||1954 Aberdare by-election||Gwynfor Evans||5,671||16.0||2||Party later represented at Westminster|
|Plaid Cymru||1972 Merthyr Tydfil by-election||Emrys Roberts||11,852||37.0||2||Party previously and later represented at Westminster|
|Plaid Cymru||1946 Ogmore by-election||T. R. Morgan||5,685||29.4||2||Party later represented at Westminster|
|People Before Profit||2011 Belfast West by-election||Gerry Carroll||1,751||7.6||3||Two members elected to the Dáil in 2011|
|Reform UK||2021 Old Bexley and Sidcup by-election||Richard Tice||1,432||6.6||3|
|Respect||2004 Birmingham Hodge Hill by-election||John Rees||1,282||6.3||4||George Galloway MP was a party member, but was usually considered Independent Labour in Parliament at the time|
|Respect||2004 Leicester South by-election||Yvonne Ridley||3,724||12.7||4||George Galloway MP was a party member, but was usually considered Independent Labour in Parliament at the time|
|SDLP||2018 West Tyrone by-election||Daniel McCrossan||6,254||17.9||3||Party represented in the Northern Ireland Assembly and historically at Westminster|
|SNP||1946 Glasgow Bridgeton by-election||M. Wood||2,575||13.9||4||Party previously and later represented at Westminster|
|SNP||1961 Glasgow Bridgeton by-election||Ian MacDonald||3,549||18.7||3||Party previously and later represented at Westminster|
|SNP||1967 Glasgow Pollok by-election||George Leslie||10,884||29.2||3||Party previously and later represented at Westminster|
|SNP||1970 South Ayrshire by-election||Sam Purdie||7,785||19.9||3||Party previously and later represented at Westminster|
|SNP||1962 West Lothian by-election||William Wolfe||9,750||23.3||2||Party previously and later represented at Westminster|
|Scottish Socialist||2000 Falkirk West by-election||Iain Hunter||989||5.1||4||Party represented in the Scottish Parliament|
|Scottish Socialist||2000 Glasgow Anniesland by-election||Charlie McCarthy||1,441||7.2||5||Party represented in the Scottish Parliament|
|Scottish Socialist||1999 Hamilton South by-election||Shareen Blackall||1,847||9.5||3||Party represented in the Scottish Parliament|
|SDP||1991 Neath by-election||John Warman||1,826||5.3||5||Party of same name which was dissolved in 1990 was represented in Parliament|
|Socialist Alliance||2000 Preston by-election||Terry Cartwright||1,210||5.7||4|
|Socialist Alliance||2000 Tottenham by-election||Weyman Bennett||885||5.4||4|
|Socialist Labour||1996 Barnsley East by-election||Ken Capstick||949||5.3||4|
|Socialist Labour||1996 Hemsworth by-election||Brenda Nixon||1,193||5.4||4|
|Socialist Labour||2002 Ogmore by-election||Christopher Herriot||1,152||6.3||5|
|UKIP||2004 Hartlepool by-election||Stephen Allison||2,347||10.2||3||Party represented in the European Parliament|
|UKIP||2006 Bromley and Chislehurst by-election||Nigel Farage||2,347||8.1||3||Party represented in the European Parliament|
|UKIP||2009 Norwich North by-election||Glenn Tingle||4,068||11.8||4||Party represented in the European Parliament|
|UKIP||2011 Oldham East and Saddleworth by-election||Paul Nuttall||2,029||5.8||4||Party represented in the European Parliament|
|UKIP||2011 Barnsley Central by-election||Jane Collins||2,953||12.2||2||Party represented in the European Parliament|
|UKIP||2011 Feltham and Heston by-election||Andrew Charalambous||1,276||5.5||4||Party represented in the European Parliament|
|UKIP||2012 Cardiff South and Penarth by-election||Simon Zeigler||1,179||6.1||5||Party represented in the European Parliament|
|UKIP||2012 Corby by-election||Margot Parker||5,108||14.3||3||Party represented in the European Parliament|
|UKIP||2012 Rotherham by-election||Jane Collins||4,648||21.8||2||Party represented in the European Parliament|
|UKIP||2012 Middlesbrough by-election||Richard Elvin||1,990||11.8||2||Party represented in the European Parliament|
|UKIP||2012 Croydon North by-election||Winston McKenzie||1,400||5.7||3||Party represented in the European Parliament|
|UKIP||2013 Eastleigh by-election||Diane James||11,571||27.8||2||Party represented in the European Parliament|
|UKIP||2013 South Shields by-election||Richard Elvin||5,988||24.2||2||Party represented in the European Parliament|
|UKIP||2014 Wythenshawe and Sale East by-election||John Bickley||4,301||18.0||2||Party represented in the European Parliament|
|UKIP||2014 Newark by-election||Roger Helmer||10,028||25.9||2||Party represented in the European Parliament|
|UKIP||2014 Heywood and Middleton by-election||John Bickley||11,016||38.7||2||Party represented in the European Parliament, and also represented in the House of Commons following the Clacton by-election the same day.|
|UUP||2018 West Tyrone by-election||Chris Smyth||2,909||8.3||4||Party represented in the Northern Ireland Assembly and historically at Westminster|
|Workers' Party||1986 Belfast North by-election||Seamus Lynch||3,563||11.8||3|
|Workers' Party||1986 Lagan Valley by-election||John Lowry||3,328||9.3||2|
|Workers' Party||1986 Upper Bann by-election||Tom French||6,978||19.2||2|
|Workers Party||2021 Batley and Spen by-election||George Galloway||8,264||21.9||3|
It is unusual for one of the major parties to finish outside of the top three in England and Wales (or outside of the top four in Scotland). It is also unusual for the principal opposition party to suffer a significant reverse in its share of the vote or ranking.
Notes 1Excluding the 1931 Westminster St George's by-election and the 1930 Paddington South by-election, which were essentially intra-Conservative contests, the previous worst result was, ironically, the 1930 Bromley by-election
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